A box contains $6$ red jelly beans, $11$ green jelly beans, and $4$ blue jelly beans. If a jelly bean is randomly chosen, what is the probability that it is not red?
There are $6 + 11 + 4 = 21$ jelly beans in the box. There are $6$ red jelly beans. That means $21 - 6 = 15$ are not red. The probability is $ \frac{15}{21} = \dfrac{5}{7}$.